Li-ion batteries have been widely used in more and more fields and, especially, have shown fine application prospect in electric vehicle (Electric Vehicle, EV) and hybrid electric vehicle (Hybrid Electric Vehicle, HEV) fields. The Li-ion battery has become the focus of new energy vehicles. Currently, a positive electrode material for a Li-ion battery is mainly lithium iron phosphate or ternary material (NCM or NCA). The ternary lithium nickel cobalt manganese (NCM) oxide material has attracted attentions from researchers due to its high battery capacity (up to 250 mAh/g, reaching 91% of the theoretical battery capacity), good safety performance, and low price. However, for a power battery, the safety performance, the rate performance, and the cycle performance are its key properties. For the NCM material, a balance among the safety performance, the rate performance, and the cycle performance is a bottleneck limiting its application in the power battery field.
At present, modified methods of NCM material mainly include: phase doping and surface coating. Element of phase doping is Mg, Al, or Ti. Material for coating is usually metal oxide, such as Al2O3or TiO2. The safety performance of modified NCM is improved to a certain extent, but the capacity density of NCM is negatively affected, since the material for coating has poor conductivity and thus poor ionic conduction. In addition, the material coated by conductive polymer has poor processability. These problems limit the application of NCM in the power battery.
In order to prevent the above-mentioned problems, the present application is proposed.